Throughout all their ups and downs, one thing has remained consistent about WWE - the company makes money. Sure, there were some lean times in the 1990s, and yes, the poor initial performance of the WWE Network in 2014 made that year an overall money-loser, but even with all of Vince McMahon's failures outside wrestling, the company has generated enough to make him and his family very wealthy.
Still, as CM Punk famously said of McMahon in his 2011 "pipe bomb" promo, "He's a millionaire who should be a billionaire." For all of McMahon and Co.'s success in promoting wrestling over the last 35 years, there have been several opportunities to make even more money that, for whatever reason, they've simply allowed to pass them by.
Typically, those instances involve hot stars whom the company didn't push in a manner befitting their fan reaction - men and women who could have drawn some serious cash for themselves and the company, but were overlooked, typically for political reasons. There are also instances where personal feelings got in the way of what could have been very interesting storylines.
Finally, there have been times when what went wrong is anybody's guess...